1. Field
The present invention relates to a universal plug and play (UPnP) remote access server (RAS) and method of supporting multiple remote accesses, and more particularly, to an UPnP RAS and method of supporting multiple remote accesses for UPnP devices of a plurality of remote networks by enabling an RAS of a home network to accept a remote access connection from the UPnP devices of the plurality of remote networks, synchronizing network images between the networks, and routing a device control message.
2. Description of the Related Art
With the recent popularity of home networks, a conventional PC network-oriented environment increasingly extends to an environment including home appliances using various lower network techniques. Therefore, a universal plug and play (UPnP) technology has been proposed in order to network these home appliances in a unified manner by using an Internet protocol (IP). The UPnP device architecture 1.0 enables home appliances to be peer-to-peer networked on the basis of a distributed and open networking structure instead of being under centralized control.
The UPnP device architecture 1.0 uses the distributed and open networking to discover a UPnP device via an IP multicast in a home network. However, an IP multicast service is not guaranteed to be normally provided within the range of the Internet, making it impossible to control the UPnP device via the Internet since such control of the UPnP device needs information obtained by discovering the UPnP device.
Therefore, a UPnP remote access architecture has been proposed to allow the UPnP device or a control point (CP) to operate normally as if both are physically in the same network, even when the UPnP device or the CP is physically separated far from the home network. The UPnP remote access architecture defines a remote access server (RAS) within the home network and a remote access client (RAC) within a remote network.